Compost Ventilation

ABSTRACT

The invention relates to a method of ventilating a compost heap. The method comprises using at least one ventilation pipe and an air moving means, the ventilation pipe comprising a pipe wall defining a conduit for gas and the ventilation pipe having a connection end and a ventilation portion, the ventilation portion having a plurality of aeration holes extending through the pipe wall and the method comprising the steps of: constructing a compost heap comprising compostable materials; inserting the ventilation portion of the at least one ventilation pipe into the compost heap; connecting the connection end of the ventilation pipe to the air moving means; using the air moving means to cause movement of air through the aeration holes; in which the step of inserting the ventilation portion into the compost heap comprises the steps of: coupling the ventilation pipe to a piler apparatus; using the piler apparatus to drive the ventilation pipe into the compost heap; releasing the piler apparatus from the ventilation pipe; and retrieving the piler apparatus from the ventilation pipe.

BACKGROUND

a. Field of the Invention

The present invention relates to a method of ventilating a compost heap,in particular to the ventilation of compost heaps and windrows so as toreduce odour.

b. Related Art

Composting of compostable material is typically performed in heaps.These heaps may be located inside buildings or outside. If the compostheap is located outside, it is typically in the form of an elongate rowcalled a windrow. Compost heaps may be agitated or turned during thecomposting process to aerate the content to ensure efficient composting.Compostable material is used herein to include biodegradable materialssuch as household waste and other waste materials.

It is known to have vent channels located on the floor of a building inwhich a compost heap is to be located. The vent channels in the flooreither blow air into the base of the compost heap, or draw air from thebase of the heap. This air movement through the base of the heapventilates the heap and therefore promotes more rapid and evencomposting of the material in the pile and removes the need to manuallyor mechanically turn or aerate the heap.

However, such vent channels can be costly to build into the, typicallyconcrete, floor. To avoid the cost of building the vents into the floorit is known to locate vent channels on the surface of the floor. Howeverthe channels are constructed on the floor they are vulnerable to damageby machinery used to transport the compost material as the compost heapis built over the channels. The channels also tend to fill with debrisand liquid leachate from the heap and require frequent cleaning toensure that the channels are still open for air flow.

It is an object of the present invention to provide improved ventilationof a compost heap.

SUMMARY OF THE INVENTION

The invention provides a method of ventilating a compost heap using atleast one ventilation pipe and an air moving means, the ventilation pipecomprising a pipe wall defining a conduit for gas and the ventilationpipe having a connection end and a ventilation portion, the ventilationportion having a plurality of aeration holes extending through the pipewall and the method comprising the steps of: constructing a compost heapcomprising compostable materials; inserting the ventilation portion ofthe at least one ventilation pipe into the compost heap; connecting theconnection end of the ventilation pipe to the air moving means; usingthe air moving means to cause movement of air through the aerationholes; the step of inserting the ventilation portion into the compostheap comprises coupling the ventilation pipe to a piler apparatus andusing the piler apparatus to force the ventilation pipe into the compostheap. When the ventilation pipe has been forced into the requiredposition, the piler apparatus is released from the ventilation pipe andretrieved from the ventilation pipe. If a plurality of ventilation pipesare being used, this step can be repeated as often as required to insertall the ventilation pipes. The ventilation pipes may be adapted toinclude a coupling portion adapted to be coupled to a coupling portionof the piler apparatus. The ventilation pipes preferably also include anose portion adapted to penetrate the compost heap during the pilingoperation.

The ventilation pipes may be inserted into the compost heap as it isconstructed, but it is preferred that the ventilation pipes are insertedafter construction of the heap as this speeds up the construction of theheap as there is no need to stop construction to arrange the ventilationpipes before the remainder of the heap is constructed.

It is preferred that the piler apparatus is compressed air powered, forexample it may be the Grundomat™ from TT UK Limited. Such pilers includea head portion that reciprocates rapidly to drive the piler through thematerial.

It is preferred that the apparatus includes a controller and at leastone sensor for measuring a physical property related to the compostheap, for example the moisture content, temperature or other propertywithin the compost heap or in the air drawn from the compost heap. Thecontroller receiving a signal from the at least one sensor, comparingthat signal with a desired signal and controlling the air moving meansto adjust the flow rate of air through the aeration holes in response tosaid signal. The controller preferably receives signals from a pluralityof sensors.

The ventilation pipes may be of any suitable size, but are preferablysubstantially straight and have a diameter between 60 mm and 100 mm. Thediameter depends upon the depth of the heap, with a deeper heappreferably being provided with a wider ventilation pipe. The ventilationportion may comprise the entire length of the pipe within the heap, butpreferably is between 500 cm and 1500 cm in length and includes aplurality of ventilation apertures of between 6 mm and 25 mm indiameter. The length of the ventilation portion is preferably about 500cm for a 3 m heap, with the length increasing to 1500 cm for a 5 m heap.The total area of ventilation apertures is preferably selected so thatit is not greater than the cross sectional area of the ventilation pipe.There is preferably one ventilation pipe for a heap volume of between 30m³ and 80 m³ and most preferably one per 50 m³.

The ventilation pipe may be made from a plastics material as suchmaterials are relatively cheap and easy to work with and are resistantto corrosion, but the ventilation pipes may be fabricated from anysuitable material and is preferably fabricated from steel as this isresistant to the forces involved in the pile driving operation.

The flow rate of air through the ventilation pipes is preferably chosento maintain the correct aeration of the compost. This flow rate dependsupon the state of composting in the heap with a newer heap requiring ahigher flow rate of air which gradually reduces as the compostingprocess proceeds. The flow of air may be controlled based upon thetemperature of the heap detected by in heap temperature sensors with ahigher temperature resulting in a higher flow of air. The air flow maybe pulsed, with periods of constant flow separated with periods of noflow. For example, a hot heap may have 15 minutes of air flow per hour,while a cooler heap requires only 6 minutes per hour of air flow at thesame rate.

Therefore, the invention provides a method for constructing a compostingapparatus comprising a compost heap comprising compostable material, atleast one ventilation pipe and air moving means, the ventilation pipecomprising a pipe wall defining a conduit for gas and the ventilationpipe having a connection end and a ventilation portion, the ventilationportion having a plurality of aeration holes extending through the pipewall and a wherein the ventilation portion is located within the compostheap and the connection end is coupled to the air moving means suchthat, when active, the air moving means causes movement of air throughthe aeration holes.

By having a ventilation pipe with a ventilation portion within thecompost heap the ventilation of the heap is more uniform as air is beingmoved from with the heap rather than at an outer surface of the heap.Aeration of the heap can be achieved by blowing air into the heapthrough the ventilation pipe, or by drawing air through the ventilationpipe, thereby causing air to be drawn through the compost heap towardthe ventilation portion. The drawing of air into the ventilation pipecan also help to prevent the heap from drying out as moisture is drawninto the heap rather than being blown to the external surfaces fromwhich it can easily evaporate. The drawing of air into the heap alsohelp to control odour as the volatile chemicals are retained within theheap rather than being blown outwards.

The aim is to promote aerobic digestion of the material. Such digestiongenerates heat and this heat tends to concentrate in a top core. Bypositioning the ventilation portion below the top core and drawing airinto the ventilation pipe, the concentration of heat can be drawndownwards towards the ventilation portion by the movement of the airthrough the ‘hot spot’.

It is preferred that there are a plurality of ventilation pipes havingventilation portions within the compost heap so that the aeration isdistributed throughout the compost heap as this helps to avoid ‘hotspots’ or areas of high or low aeration.

The ventilation pipe is preferably arranged substantially verticallywithin the compost heap such that the connection end extends above anupper surface of the heap. This facilitates connection of theventilation pipe to the air moving means and can help to prevent theventilation pipe from filling with compost material which may occur ifmaterial can fall through the aeration holes.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be further described, by way of example, withreference to the accompanying drawings, in which:

FIG. 1 shows a cross section through a windrow compost heap;

FIGS. 2 a, 2 b and 2 c shows a cross section through a compost heap as aventilation pipe is inserted into the compost heap;

FIG. 3 shows a cross section through an end of a ventilation pipe.

DETAILED DESCRIPTION

FIG. 1 shows a composting apparatus 1 comprising a compost heap 2comprising compostable material. There is at least one ventilation pipe4 and air moving means 6, in this case a fan. The ventilation pipe 4comprised a pipe wall 8 defining a conduit 10 for gas. The ventilationpipe 4 has a connection end 10 and a ventilation portion 12. Theventilation portion 12 has a plurality of aeration holes 14 extendingthrough the pipe wall 8. The ventilation portion 12 is located withinthe compost heap 2 and the connection end 10 is coupled to the airmoving means 6 by a pipe 16 such that, when active, the air moving means6 causes movement of air through the aeration holes 14 towards the airmoving means 6. In this case the ventilation pipe is a 76 mm outerdiameter steel pipe having a wall thickness of 3 mm.

The air moving means 6 comprise a controller 18, an air mover 20, afilter 22 and a sensor 24. The controller 18 receives a signal from thesensor 24 and controls the air mover 20, in this case a fan blower, inresponse to said signal. It should be understood that the apparatuscould function without the sensor with the controller 18 simplycontrolling the air mover 20 at a constant speed depending upon whetherthe air moving means is active or not, for example the controller couldbe a simple switch.

The air drawn from the heap 2 is passed through filter 22 for treatmentto substantially reduce the odour of the gas before it is vented toatmosphere through vent 26.

This compost heap 30 could be located inside a building on a concretebase, but could also be a windrow compost heap located outdoors on anysurface, for example a surface of a field.

FIG. 1 also shows a further ventilation pipe 104 located in the compostheap 2 and coupled to the same air moving means. It is possible thateach ventilation pipe could have its own air moving means, but a singleair moving means is preferred.

FIG. 2 a shows an initial stage in the ventilation of a compost heap 30using a ventilation pipe 32 having a ventilation portion 34 and aconnection end 36. A compressed air powered piler 38 dimensioned so asto fit through the ventilation pipe 32 is provided to create the hole inwhich the ventilation pipe 32 will be arranged. The piler 38 includes anair line 40 leading to a source of compressed air (not shown).

The piler 38 includes a coupling means 42 which includes a taper 58adapted to couple to coupling means 44 in the nose 50 at an end of theventilation pipe opposite the connection end 36. the coupling means 44include a female taper 56 which is adapted to engage with the taper 58.

FIG. 2 b shows the ventilation pipe 32 and piler 38 coupled together byengagement between the coupling means 42 and 44. The piler 38 is actingas an internal pile driver within the ventilation pipe 4 and driving itinto the compost heap 30. This process will continue until theventilation pipe 32 has reached a desired depth.

FIG. 2 c shows the ventilation pipe 32 in position within the compostheap 30. The coupling means 42,44 have been disengaged and the piler 38retrieved from the ventilation pipe 32. A compressed air line 46 iscoupled to the connection end 36 and compressed air blown into theventilation pipe 32 to blow debris from the aeration holes 14. The airline 46 is then removed and the connection end 36 connected to airmoving means as shown in FIG. 1.

FIG. 3 shows a ventilation pipe 4 having a nose portion 50 adapted topenetrate the compost heap during the piling operation. The nose portion50 includes a shoulder 52 which contacts the wall 8 of the ventilationpipe 4 and is welded thereto to secure the nose portion 50 to theventilation pipe 4. The nose portion comprises a substantially solidmachined truncated cone shaped tip 54 which allows for increasedpenetration of the ventilation pipe 4 into the compost heap 2 during thepiling operation. The nose portion further includes a male taper section56 which engages with a female protrusion of the piler apparatus 58 toform a Morse taper type engagement although other engagement means couldbe used. This outer shape of the tip 54 is one example of an adaptationto enable deeper penetration into the compost. The tip 54 preferably hasa tapered shape such that a leading end has a smaller cross sectionalarea than the ventilation pipe. The leading end could be pointed ortruncated and the cross section could be any suitable shape such asstar, square, oval or circular. The nose portion may be integrallyformed with the ventilation pipe, or attached by welding, or attachmentmeans such as a screw thread or bayonet fitting. The nose portion ispreferably substantially solid.

It should be understood that the invention has been described above byway of example only and that modifications in detail may be made withoutdeparting from the scope of the invention as described in the claims.

1. A method of ventilating a compost heap using at least one ventilation pipe and an air moving means, the ventilation pipe comprising a pipe wall defining a conduit for gas and the ventilation pipe having a connection end and a ventilation portion, the ventilation portion having a plurality of aeration holes extending through the pipe wall and the method comprising the steps of: constructing a compost heap comprising compostable materials; inserting the ventilation portion of the at least one ventilation pipe into the compost heap; connecting the connection end of the ventilation pipe to the air moving means; using the air moving means to cause movement of air through the aeration holes; in which the step of inserting the ventilation portion into the compost heap comprises the steps of: coupling the ventilation pipe to a piler apparatus; using the piler apparatus to drive the ventilation pipe into the compost heap; releasing the piler apparatus from the ventilation pipe; and retrieving the piler apparatus from the ventilation pipe.
 2. A method as claimed in claim 1, in which the air moving means are used to draw air from the ventilation pipe and draw air through the aeration holes into the ventilation pipe.
 3. A method as claimed in claim 1, in which the piler apparatus is powered by compressed air.
 4. A method as claimed in claim 1, in which compressed air is blown into the ventilation pipe after insertion such that air is forced out through the aeration holes substantially clearing them of debris that may hinder air flow.
 5. (canceled) 